Its about a boy who just went to a parade or is going to a parade and he sees something at the parade then that night he goes to sleep and people come get him in some kind of airship and he goes to another place where there is a princess I can't remember why he is there but there is a shadow thing behind a door that he lets out and he has to figure out how to fix it.

Little nemo, adventures in slumberland

little nemo, adventures in slumberland

Thank you I kept thinking it was something with nimo but everyone said I was thinking of the fish movie.